[Solved] CS2030s Lab 3-Snatch!

Topic Coverage

• Abstract Classes / Interfaces
• Inheritance vs Composition
• Design Principles
• CS2030 Java Style Guide
• CS2030 Java Documentation

Problem Description

Snatch is yet another transport service provider trying to vie for a place in the public transport arena.

Snatch provides three types of ride services:

• JustRide
  • Fare is based on the distance @ 22 cents per km
  • Fare is the same regardless of the number of passengers (pax)
  • There is no booking fee.
  • A surcharge of 500 cents if a ride request is issued between the peak hour of 600 hrs to 900 hrs, both inclusive
• TakeACab
  • Fare is based on the distance @ 33 cents per km, but there is a booking fee of 200 cents
  • Fare is the same regardless of the number of passengers (pax)
  • No peak hour surcharge
• ShareARide
  • Fare is based on the distance @ 50 cents per km
  • Fare is divided equally among the number of passengers
  • There is no booking fee.
  • Any fractional part of the fare is absorbed by your friendly driver
  • A surcharge of 500 cents if a ride request is issued between 600 hrs to 900 hrs, both inclusive

In addition, there are two types of drivers under Snatch. Each can provide a subset of the services above.

• NormalCab drivers provide JustRide and TakeACab services.
• PrivateCar drivers provide JustRide and ShareARide services.

A customer can issue a Snatch ride request, specified by the distance of the ride, the number of passengers, and the time of the request.

Task

You shall be given a request, followed by a list of NormalCab or PrivateCar drivers together with their corresponding waiting times. A booking is a pairing of a driver with the request. The task is to find the best booking with the lowest fare by matching the available drivers based on the services they provide to the given request. Break ties among the same lowest fares by selecting the booking with the smaller waiting time.

You may assume that no two bookings have the same fare and the same waiting time.

This task is divided into several levels. Read through all the levels to see how the different levels are related.

Remember to:

• always compile your program files first before using jshell to test your program
• use checkstyle and javadoc comments to enhance code readability and facilitating code review

$ javac your_java_files$ jshell -q your_java_files_in_bottom-up_dependency_order < test1.jshjshell> new Request(20, 3, 1000)$.. ==> 20km for 3pax @ 1000hrsjshell> new Request(10, 1, 900)$.. ==> 10km for 1pax @ 900hrsjshell> /exit

$ javac your_java_files$ jshell -q your_java_files_in_bottom-up_dependency_order < test2.jshjshell> new JustRide()$.. ==> JustRidejshell> new JustRide().computeFare(new Request(20, 3, 1000))$.. ==> 440jshell> new JustRide().computeFare(new Request(10, 1, 900))$.. ==> 720jshell> new TakeACab()$.. ==> TakeACabjshell> new TakeACab().computeFare(new Request(20, 3, 1000))$.. ==> 860jshell> new TakeACab().computeFare(new Request(10, 1, 900))$.. ==> 530jshell> /exit

$ javac your_java_files$ jshell -q your_java_files_in_bottom-up_dependency_order < test3.jshjshell> new NormalCab("SHA1234", 5)$.. ==> SHA1234 (5 mins away) NormalCabjshell> new Booking(new NormalCab("SHA1234", 5), new Request(20, 3, 1000))$.. ==> $4.40 using SHA1234 (5 mins away) NormalCab (JustRide)jshell> new NormalCab("SHA2345", 10)$.. ==> SHA2345 (10 mins away) NormalCabjshell> new Booking(new NormalCab("SHA2345", 10), new Request(10, 1, 900))$.. ==> $5.30 using SHA2345 (10 mins away) NormalCab (TakeACab)jshell> Booking b1 = new Booking(new NormalCab("SHA2345", 10), new Request(10, 1, 900))jshell> Booking b2 = new Booking(new NormalCab("SHA2345", 10), new Request(10, 1, 900))jshell> b1.compareTo(b2) == 0$.. ==> truejshell> Booking b3 = new Booking(new NormalCab("SHA1234", 5), new Request(10, 1, 900))jshell> Booking b4 = new Booking(new NormalCab("SHA2345", 10), new Request(10, 1, 900))jshell> b3.compareTo(b4) < 0$.. ==> truejshell> /exit

$ javac your_java_files$ jshell -q your_java_files_in_bottom-up_dependency_order < test4.jshjshell> new ShareARide()$.. ==> ShareARidejshell> new PrivateCar("SMA7890", 5)$.. ==> SMA7890 (5 mins away) PrivateCarjshell> new Booking(new PrivateCar("SMA7890", 5), new Request(20, 3, 1000))$.. ==> $3.33 using SMA7890 (5 mins away) PrivateCar (ShareARide)jshell> new PrivateCar("SLA5678", 10)$.. ==> SLA5678 (10 mins away) PrivateCarjshell> new Booking(new PrivateCar("SLA5678", 10), new Request(10, 1, 900))$.. ==> $7.20 using SLA5678 (10 mins away) PrivateCar (JustRide)jshell> Booking b1 = new Booking(new PrivateCar("SMA7890", 5), new Request(10, 1, 900))jshell> Booking b2 = new Booking(new PrivateCar("SLA5678", 10), new Request(10, 1, 900))jshell> b1.compareTo(b2) < 0$.. ==> truejshell> /exit

$ javac your_java_files$ jshell -q your_java_files_in_bottom-up_dependency_order level5.jsh < test5.jshjshell> findBestBooking(new Request(20, 3, 1000),    ...> new Driver[]{new NormalCab("SHA1234", 5), new PrivateCar("SMA7890", 10)})$.. ==> $3.33 using SMA7890 (10 mins away) PrivateCar (ShareARide)jshell> findBestBooking(new Request(10, 1, 900),    ...> new Driver[]{new NormalCab("SHA1234", 5), new PrivateCar("SMA7890", 10)})$.. ==> $5.30 using SHA1234 (5 mins away) NormalCab (TakeACab)